Poison of the Heart
by demonicnargles
Summary: A story about how Naruto copies the style of jyuuken, to deadly effect. Now he is a killer, who continues on in hopes of redeeming himself. In hopes of atoning for his accidental crime. NaruHina. Dark. One-shot.


Poison of the Heart

A story about how Naruto copies the style of jyuuken, to deadly effect. Now he is a killer, who continues on in hopes of redeeming himself. In hopes of atoning for his accidental crime. NaruHina. Dark. One-shot.

N.B. This one-shot is based on the lengthy (and harsh sad face) critique of 'The Deadliest Poison', from ArmorOfGeddon. He had quite a number of good objections to the story, and suggestions on how to improve it. Thus, 'Poison of the Heart', a more realistic view of what would happen in this case. The first bit of the story is exactly the same as 'The Deadliest Poison', until the end of the fight, or thereabouts.

Thank you to ArmorOfGeddon for your helpful review.

* * *

Naruto growled as he stood up through the pain. His entire body ached after Neji's last attack. Stupid jyuuken, sealing off his chakra.

But then Naruto smiled. Just _his_ chakra. He formed as simple seal to help him concentrate and began to draw power from the seal.

Neji scoffed, thinking that Naruto was futilely trying to draw up his own chakra. "I've sealed it off, Naruto. You won't be able to use chakra for at least a few hours. Give up. It was not your fate to win this fight."

Naruto just grinned and pulled a little harder. _Pop, pop, popopopopopopop_. Kyuubi's chakra forced its way out of the sealed tenketsu, quickly wrapping the blonde in a thin red mist before it faded out of sight.

Naruto smirked and dropped into his normal fighting stance, one that he had made on his own so long ago, when he figured out that the Academy instructors were not helping him at all.

Neji frowned. It should _not_ have been possible to unseal chakra so quickly. How on earth had Naruto done so, and what was this strange red chakra?

The Hyuuga prodigy fell into his jyuuken stance, gathered his chakra, and attacked again. _This _time, it would be 128 palms, and then Naruto would be finished.

As Neji rocketed forward, Naruto had a sudden idea. Why not try a little Jyuuken himself? Of course, he didn't have the skill to see tenketsu, so he'd just be guessing… Naruto decided it didn't matter. With Kyuubi's seemingly infinite chakra at his disposal, he could just make up for his lack of skill with pure power.

Neji almost tripped when he saw Naruto change into a fairly good imitation of the jyuuken stance. What was that idiot thinking, mocking the Hyuuga like that?

But as Neji approached, he realized that Naruto truly intended to fight like that. He saw the strange red chakra gathering in the blonde's hands, ready to strike. Man, that was a lot of chakra.

But Neji had speed and skill. He deftly dodged Naruto's first clumsy attempt at jyuuken and tap a tenketsu on the idiot's chest. _Pop_. Almost instantly it unsealed itself in a flicker of red chakra.

Neji was confused for just a moment, but that moment was long enough for Naruto to strike. Imitating Neji's last attack, Naruto struck Neji in about the same place the white-eyed boy had hit him. Naruto had no idea if he had gotten a tenketsu, but just to be safe, he shoved a huge amount of chakra into the attack.

Neji flew back several dozen feet, and landed in a heap, clutching his chest. If the Hyuuga had been the kind to curse, the air would have been filled with obscenities. As it was, he merely curled into the fetal position, and pulled his head back. His mouth stretched open in a silent scream.

Pain. So much pain. Even though the attack had missed the tenketsu by a good quarter-inch, which, in normal jyuuken, was a complete whiff, Naruto had pushed so much chakra into the attack that it didn't matter. Much of it had gotten to the tenketsu anyway, sealing it in some new, incredibly painful manner.

And it only got worse. Instead of fading away as the shock wore off, the agony intensified, as if the chakra were burning him from inside. Steeling himself against the pain, Neji stood up and took his jyuuken stance again, shaking slightly.

The white-eyed boy rushed forward, now much more careful to avoid getting hit. He hit several tenketsu in less than a second, easily avoiding Naruto's slow reactive attacks. But the tenketsu wouldn't stay closed. By the time that Neji had gotten to 32 strikes, every tenketsu he'd hit in the 16-set and before was already open again. The same with 64, and with 128.

By the time Neji leapt away, winded after the exertion, and wincing at the continually growing pain, all of Naruto's tenketsu were completely open, as if nothing had happened.

Naruto sprang forward to attack, looking like a slower, blonde version of Neji. The Hyuuga dodged and dodged, growing slower because of the pain, even as Naruto sped up as he really got into it. Red chakra flew past the white-eyed boy with every failed attack.

Neji couldn't dodge one blow, so he blocked it with a hand. Just a slight tap to divert the blow, but Neji's hand was instantly engulfed in screaming agony. Perhaps because it was so small, compared to the amount of chakra in Naruto's strike, it grew worse at an accelerated rate. The pain quickly became unbearable, so Neji blocked off feeling in that hand with a quick jyuuken strike to his own wrist.

But that couldn't keep him from noticing that his hand slowly paled, became gray, and then began to turn black. The darkness began to seep down his arm, causing pain all along the forearm. The skin there turned deathly pale, and began to fade to gray.

But Neji had no time to prevent the pain in his arm. He was too busy dodging the furious flurry of attack that the blonde now unleashed. As his arm worsened, he realized that he could no longer move it with precision. The pain in his chest was now a constant, excruciating torment. His breaths became labored as his chest tightened involuntarily.

Neji turned to the side, putting his bad arm behind him, since he could no longer move I adequately enough to avoid getting hit. Neji coughed, tasting blood, and feeling it leak from his mouth and nose. What was going on? He could vaguely see the chakra inside him moving, as if with its own will, but he had no time to ponder it.

Naruto got another hit in, tapping Neji's stomach. The Hyuuga doubled over in tortured agony, passing out before he hit the ground.

The announcer declared Naruto the winner, and medics removed Neji from the field.

Within minutes, the Hyuuga prodigy was no longer able to breathe. He died shortly after.

* * *

Naruto was rather pleased with himself. Beating last year's number one genin was no mean feat, and he had done it without too much difficulty, other than using the fox's chakra to reopen his tenketsu.

Turning when someone tapped him on the shoulder, his stared into the animal mask of one of the ANBU.

"Uzumaki-san, come with me."

A little surprised, Naruto followed quickly. The ANBU walked into the halls underneath the stadium, around several corners, and stopped outside one of the medical facility's doors.

Assuming correctly that he was supposed to go inside, Naruto opened the door and stepped in. Almost immediately, the sickening stench of burnt and rotting skin, especially strong to his abnormally powerful sense of smell, hit him with a wave of nausea. Even more sickening was the figure on the table.

It was Neji. Or, it looked like it could have been Neji once.

The late Hyuuga branch member, dressed in only his shorts, lay unmoving on the table. His skin was a weird gray color, with black splotches on his chest, his stomach, and on one arm. In the middle of several of the larger spots of black, there were holes in the skin, which smoked slightly, and was the obvious source of the terrible odor.

Naruto gasped and fell to the ground, barely suppressing his urge to gag. What on earth had happened to Neji?

A man he had not noticed before stepped forward from where he had stood next to the wall. A tall man with pure white eyes.

"Uzumaki Naruto, you have killed my nephew, Neji." Naruto gasped and sputtered for an answer, but the man cut him off. "Your bastardized version of our clan techniques poisoned him, causing him to die in terrible agony. I don't think I need to tell you exactly how you poisoned him."

When Naruto did not reply, and appeared confused, the tall Hyuuga continued. "You poisoned him with chakra that you pulled from within yourself. From a source that is forbidden to mention."

Naruto eye's widened in comprehension. The Kyuubi's chakra was poisonous? How had Naruto survived all these years with it, if it had killed Neji within minutes?

His accuser walked out of the door, uttering a soft threat as he left.

"Beware, Uzumaki. I, Hyuuga Hiashi, will take vengeance for this foul murder."

Naruto remained on his knees in the room, tears slowly running down his cheeks. He had killed Neji? A fellow genin? A fellow ninja of Konoha?

Naruto rocked himself back and forth, back and forth. He felt sick, even beyond the physical illness from the sight and smell of Neji's rotting corpse, which still simmered slightly as the demonic chakra continued to eat away the body.

Naruto vision began to tunnel, and his breaths came in shorter and quicker gasps. But before he could faint, the ground shook and a loud noise shattered the quiet.

Naruto, unable to think clearly, still managed to rush outside, where a terrible scene unfolded itself before his very eyes.

Ninja were attacking. Sound and Sand ninja turned on Konoha and struck to kill. Gigantic snakes crushed the walls of the village and began destroying everything they could see.

Naruto was brought out of his reverie when a ninja sprinted towards him at a blinding speed. Naruto absentmindedly dodged, getting a kunai embedded in his side for his lack of concentration.

The Sound ninja laughed out loud. "Stupid kid, you should have run when you had the chance! Now I'm gonna kill you!"

Time stopped for Naruto, and he paused in his reflection on Neji's death. The sound-nin was going to kill him. _Kill_ him. By his uniform, he must be a chuunin or even a jounin. Naruto didn't have a chance. There was no way he could defeat him. There was no way he could kill…

There was a way. A way so terrible that Naruto shuddered to think of it. But this ninja was an enemy, right? It would be okay, right?

Right?

Some darker part of himself, some deep voice within him, assured Naruto that it would be alright. That this ninja could not be spared. That doing this horrible, terrifying deed would be alright, in this one case.

The ninja charged, and Naruto twisted out of the way of the potentially lethal attack, to gently tap the ninja in the back. With that gentle touch, he delivered a massive injection of the demon's chakra.

The man yelled in pain, and turned to face Naruto again, his eyes now squinting in pain. But before he could gather himself to strike again, he began to cough. His coughing turned into hacking, and he spit out blood and bile as he began to sicken before Naruto's very eyes.

Unable to watch anymore, Naruto turned away and listened to the poor man die, moaning in pain until the very end, several minutes later.

When the man was finally quiet, Naruto came out of his trance. There was still a battle going on. People he had to help. People he had to protect. But he was just a genin. There was nothing he could really do for them, unless…

The ominous voice persuaded him that it would be for a good cause, and that no one would think ill of him for using it on an enemy.

Naruto joined in the carnage, forming clones to surround himself with for protection. While they couldn't use the Kyuubi's chakra like the original, they could certainly distract his opponents for the real Naruto to get in one hit.

Naruto raced around Konoha, accompanied by army of clones. Tap, and a man stumbled, unaware that his life was now measured in minutes, not years. Touch, and the ninja from sand would never go home again. Poke, and the poor kunouchi's fate was sealed.

Naruto continued this, unleashing his vile weapon, a terrible poison, upon the enemy. It was not until he saw Sasuke pursue the strange misshapen sand ninja into the forest, that Naruto halted his attack. The red-headed sand guy had Sakura-chan!

Growling in a deeper voice than he normally used, Naruto raced after them, his clones following close behind. The unfortunate sound ninja who decided to catch him off guard attacked a nearby clone, which promptly burst into smoke. The real Naruto slapped him as he passed, transferring some of Kyuubi's chakra in the brief contact.

Naruto continued on, leaving Konoha behind him.

* * *

Gaara snarled and threw a hand of sand at the blonde, who quickly dodged it and closed in for a close-range attack.

More sand appeared to bat him away, but Naruto was unfazed. Just one-hit, right? Just one dose of Kyuubi's violently caustic, toxic chakra, and that was the end.

But the sand was so fast, Naruto couldn't get around it. As the blonde grew less and less afraid of killing, and more and more afraid of losing, he pulled up increasingly larger amounts of demon chakra to attack with.

The sand still pushed him away, but not as far, and not as fast. Naruto flung himself against Gaara's ultimate defense, again and again, screeching out louder and more animalistic cries as he continued.

A single scratch along the red-head's face, melting through the thin layer of sand, and Naruto smiled triumphantly. But something was different. Gaara howled and clutched his face, as yellow chakra glowed faintly around the wound. Gaara's eyes were open wide, in pain and effort, but he seemed able to stop the poison.

Naruto growled, a low, angry rumble from deep within his chest. It wasn't working. Because of the other demon, or whatever it was? At any rate, the wound seemed to have distracted it.

Naruto attacked again and again. Another nick. Another grazing blow. Gaara howled in pain, but the boy's own demon seemed able to handle the light doses of the deadly venom of Kyuubi.

But then Naruto, aided by ever-increasing amounts of chakra, and Gaara's distraction, and the blonde's own, building rage, he struck with a solid hit, pushing much more chakra than seemed necessary into the blow. So much that the heavy strike to Gaara's chest sent red chakra blasting out of his back.

But Gaara would not be brought down by the poison, deadly or not. The strange yellow chakra swirled visibly around the places where he had been hit, containing the damage, combating the effects.

But now, with the last hit, there was not enough chakra to both defend Gaara from Naruto's blows and to stop the poison. Little by little, as Gaara's demon was forced to block Naruto's rapidfire strikes, the poison spread. Slowly at first, then more quickly as Naruto realized what was happening, and added clones to the attack.

Soon, Gaara fainted from the pain, and Shukaku emerged, quickly growing larger than the forest, drawing sand from the desert not so far away. Naruto snarled, then roared his defiance.

_No one_ could escape Kyuubi's curse, Naruto vowed. If Neji had to die for Naruto to discover this power, then Naruto would use this power to help Konoha as much as he could. Hopefully, this would someday atone for his terrible crime.

As his resolve set, Naruto unleashed the fury of the demon within. Shukaku was large, but he was slow. Naruto dodged and danced away from the blows as he worked his way closer. Suddenly he jumped, and, taking advice from his instincts, flung as much chakra through the air as he could, in the direction of the boy on Shukaku's head.

A large sphere of evil energy, not unlike a fireball of pure red, rocketed from his hands, straight at Gaara. Also like a real fireball, it quickly dissipated in the air, but it had not disappeared entirely before it struck home.

Shukaku howled in torment as he writhed and shrunk and dissolved back into sand. Soon, Gaara's gray corpse lay rotting in the sun, black splotches spreading underneath his dead skin.

Naruto scowled, grateful to have won, but recovering from his anger, he remembered Neji, and the reason for doing this in the first place.

Gently picking up the unconscious Sakura from where Gaara had left her, Naruto set his face like stone and made his way back to Konoha. Even if this power had gotten her back, it could not excuse the way he had discovered it.

Naruto promised himself again, that he would spend his career, and give his life gladly, to atone for his sin.

* * *

Naruto returned from his latest mission, a rather distasteful one, if you asked him. But Naruto _never_ refused a mission, no matter how cruel, no matter how difficult, no matter how long. Since Neji was no longer alive, he would atone for his sin in service to Konoha.

So even though he hated the assassination missions, he never turned them down. He had done so many now, that he sometimes had trouble remembering why he had started doing them in the first place. Neji. Right. So often now, Naruto felt nothing when he killed. No longer did he see Neji's dead body with every kill. Only every so often. Once in a very long while.

Slowly, Naruto's heart hardened into that of a true shinobi.

In his last mission, the client had asked for the target to be killed in a slow and painful manner. Easily done, especially for Naruto. The less chakra he used, the more slowly the victim died. And they _always_ died. With the exception of Gaara, Naruto had never met a person who could survive his demon jyuuken.

And so Naruto had snuck into the house at night, and found the target, an aging mob boss, sleeping inside a secret room. With only the slightest prick of Kyuubi's energy, Naruto was finished, and dashed away from the house before he was spotted.

It took several hours for the tiny amount of the world's deadliest poison to end his suffering, according to reliable sources.

Once he had reported the success back to Tsunade, Naruto went home, back to the Hyuuga complex, where Hiashi was waiting for him, as always.

Despite his harsh words that fateful day, so long ago, Hiashi was not a vindictive man. And seeing Naruto's heartfelt sorrow and self-loathing over Neji's death, he had come to like the young man. But even though he had offered to let Naruto free of the agreement they had made that day, to atone for Neji's death by taking his place in the branch house, and serving the main house family when not on missions, Naruto always refused.

And so it was that Hiashi had gradually accepted the strange demon container into his home, more as a family member than a servant. Hiashi was even more grateful that Naruto had managed to convince Hinata that Neji's death was not the result of her weakness when she fought her cousin in the preliminary matches. Though she was not of sufficient quality to be heir to the Hyuuga clan, she was still his daughter, and Hiashi was glad that Naruto had helped ease her feeling of guilt.

Even now, the head of the Hyuuga felt terrible knowing what Naruto must have gone through that day, accidentally killing a fellow ninja of the leaf, then having that person's family swear veangeance…

"You're back, Naruto."

"I am, Hyuuga-sama."

The tall, white-eyed man continued their usual pattern of dialogue, which happened after every mission. "You don't have to show so much respect, Naruto. Hiashi will suffice."

"If I am to replace Neji, then I must address you with the respect he would have, Hyuuga-sama."

The clan leader sighed, knowing that it was futile, as always. "Let's go inside, Naruto. Hinata has been anxious for you to return."

"Of course, Hyuuga-sama."

Hinata met them as soon as they entered the house, and, seeing the stony look in Naruto's eyes, knew that he had taken another life. It always hurt him, even if he hid it so well that he didn't know himself. But Hinata could see it, and she spent the rest of the evening comforting him, slowly bringing him back out of the protective shell into which he withdrew before every kill.

When he fell asleep on her shoulder, she did not complain, and she did not move away. He couldn't be strong all the time. Right now, she had to be strong for him.

Blushing as she kissed his forehead, she drifted off to sleep beside him.

* * *

Naruto shook with anger as he faced the Akatsuki-nin, Kakazu. This bastard had been one of Asuma's killers! Asuma, a Konoha shinobi. Someone that Naruto had to protect, to keep safe in order to atone for his sin…

Naruto raced forward, ignoring strategy, ignoring the worried shouts from Sakura and Kakashi.

The ninja from Akatsuki smiled. If this went well, he might even be able to capture this idiot jinkuurichi in this encounter. True, he didn't know much about the demon, Kyuubi, but it seemed pretty obvious that it was a fire demon. And fire was not a problem.

Not as much of a problem as that one a while ago, an ice demon. Not fun. And even less fun than that stupid water demon had been.

Kakazu dodged and weaved around the berserk blonde, wondering how he should go about attacking. It was difficult to get a hit in edgewise, since the boy attacked so quickly and furiously that his swipes and blows were a blur.

Seeing an opening, Kakazu braced to block one hit so that he could use that delay in the jinkuurichi's attacks to strike back.

As the blow connected with his arm, Kakazu realized his mistake. A _poison_ demon. And since youki was already toxic…

Kakazu missed his opportunity to attack, so stunned by the revelation, and by the sudden pain that accompanied the rather significant amount of demonic chakra that had been forced into his arm.

But he was aware enough to spring back out of the way of Naruto's next attack. Thinking quickly, he grabbed a kunai in his good hand and cut off the poisoned arm, letting it fall to the ground with a dull thud.

But now a limb short, he had a more difficult time defending against the attacks. His balance was off, and that made it difficult to fully concentrate well.

When it became obvious that he could no longer play around, he prepared to called out his alter egos, until he suddenly realized why that would be a terrible idea. Every one of them was connected to him. If any one of them were hit, the poison would come back to him before his killed the heart outside. And it was hard to avoid getting hit if he got any larger.

He was so distracted by his revelation, that he didn't notice when Naruto exchanged himself with a clone. He failed to realize this until a sharp pain entered from behind, the sure sign of the demon's chakra, a horrifying poison, beginning its lethal work.

Kakazu, disgraced, fled the battle so that his ring would not fall into enemy hands. When he had gotten several miles away, he died. And revived as he used another heart.. And died as the still-present poison killed him again.

He died, and died, and died, and eventually, he stayed dead.

Naruto, knowing that the man from Akatsuki was finished, was not at all disturbed when he ran away.

* * *

Naruto advanced through the ranks quickly, becoming captain of the ANBU less than two years after becoming a jounin. Who could turn down the perfect assassin, who could kill with a single hit?

After a year in that position, Naruto retired. Hinata knew that he was disappointed. Naruto's self-proclaimed goal to become Hokage had never been fulfilled. But she knew why, and she knew that no amount of persuasion would make him ask for the position.

Naruto felt unworthy. His whole life revolved around atoning for his crime, an event so long ago that few really remembered it, and fewer still ever thought about it.

But for Naruto, it was his life. His reason to continue. His purpose for existing. And when Hiashi, on his deathbed, made a single request, he knew that Naruto would not refuse.

Naruto married Hinata shortly after the quiet funeral, taking the place that could have, and, in Naruto's mind, _should_ have been Neji's. Head of the clan. The elders of the Hyuuga, so used to him, and knowing that he was as much a Hyuuga as any born to the name, did not object.

No one was surprised, and no one dared object, when he named his first son, born with the Byakugan, after the long-dead prodigy from the branch house clan.

But still, the guilt ate at Naruto's heart, for a crime committed unintentionally, long, long ago. It burned inside him, causing him pain long after the event. Even though everyone else had forgiven him, he could not forgive himself.

The guilt was a venom inside him, a poison of the heart.

* * *

It wasn't great, but I hope you enjoyed it. It turned out different than I'd hoped. Oh well.

Let me know what you thought.

-demonicnargles


End file.
